add extern "C" to __errno_location's definition if in __cplusplus file

diff --git a/libc/config/linux/api.td b/libc/config/linux/api.td
index 1c9fa8a..673521f 100644 (file)
--- a/libc/config/linux/api.td
+++ b/libc/config/linux/api.td
@@ -27,6 +27,9 @@ def NullMacro : MacroDef<"NULL"> {
 
 def ErrnoMacro : MacroDef<"errno"> {
   let Defn = [{
+    #ifdef __cplusplus
+    extern "C"
+    #endif
     int *__errno_location();
     #define errno (*__errno_location())
   }];